SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '572a5be4839a6132a724b2650c0b876af227f5238ca998464c200a9803b0d310' 
  AND token = '1aUJt1GplmSrNg0G3mG4BWKkR59uUGGHxGV0lpVD+A0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}